Hydraulic ejection device

ABSTRACT

An hydraulic ejector device is presented which is completely independent and normally secured to a special holder or bolster by means of a two piece draw-bolt clamp assembly. The hydraulic quick-disconnects are attached to the two fittings on the holder. The holder is mounted on a movable slide unit or die platen by means of four nuts. The quick-disconnect device is provided so that the self-contained ejector may be quickly changed if the manufacturer desires to use more conventional holders and tooling. The ejector device is generally cylindrical in form and has a central through opening in the casing, in which are found serially from back to front a back plug, a cylindrical pressure chamber in which is a reciprocable piston having a piston extension projecting forwardly, in one embodiment an intermediate or ejector pin normally abutting the piston extension, and a formed-part die at the forward end of the casing, one wall of which is provided by the distal end of the ejector pin in its retracted position. In a second embodiment, the piston extension serves as an ejector pin. In the first embodiment, retraction of said ejector pin and motor is accomplished by the entry of a new part into the die. In the second embodiment, hydraulic fluid is introduced to drive the piston back for a second cycle. These parts in retracted position in the casing provide a sturdy column to transmit forming pressure through the back plug, the piston and the ejector pin to shape a part held in the formed-part die as two platens of a header or press approach each other. Means is then provided for introducing pressure fluid in a cylindrical pressure chamber causing the piston and the ejector pin to move forward and eject the formed part. In the cylindrical pressure chamber, there are substantially equal pressure-exposed areas in opposite directions, one against the back plug and one against the piston, so that when hydraulic fluid is introduced into the pressure chamber to cause an ejection, the entire device tends to remain stationary.

United States Patent [191 Requarth [451 Oct. 14, 1975 HYDRAULIC EJECTIONDEVICE Robert E. Requarth, 22 Shawnee Road, Greensburg, Pa. 15601 [22]Filed: June 12, 1974 [21] Appl. No.: 478,689

[76] Inventor:

Primary E.\'aminerC. W. Lanham Assistant ExaminerRobert M. RogersAttorney, Agent, or FirmBaldwin, Egan, Walling & Fetzer [57] ABSTRACT Anhydraulic ejector device is presented which is completely independentand normally secured to a special holder or bolster by means of a twopiece draw-bolt clamp assembly. The hydraulic quick-disconnects areattached to the two fittings on the holder. The holder is mounted on amovable slide unit or die platen by means of four nuts. Thequick-disconnect device is provided so that the self-contained ejectormay be quickly changed if the manufacturer desires to use moreconventional holders and tooling. The ejector device is generallycylindrical in form and has a central through opening in the casing, inwhich are found serially from back to front a back plug, a cylindricalpressure chamber in which is a reciprocable piston having a pistonextension projecting forwardly, in one embodiment an intermediate orejector pin normally abutting the piston extension, and a formed-partdie at the forward end of the casing, one wall of which is provided bythe distal end of the ejector pin in its retracted position. In a secondembodiment, the piston extension serves as an ejector pin. In the firstembodiment, retraction of said ejector pin and motor is accomplished bythe entry of a new part into the die. In the second embodiment,hydraulic fluid is introduced to drive the piston back for a secondcycle. These parts in retracted position in the casing provide a sturdycolumn to transmit forming pressure through the back plug, the pistonand the ejector pin to shape a part held in the formed-part die as twoplatens of a header or press approach each other. Means is then providedfor introducing pressure fluid in a cylindrical pressure chamber causingthe piston and the ejector pin to move forward and eject the formedpart. In the cylindrical pressure chamber, there are substantially equalpressure-exposed areas in opposite directions, one against the back plugand one against the piston, so that when hydraulic fluid is introducedinto the pressure chamber to cause an ejection, the entire device tendsto remain stationary.

4 Claims, 6 Drawing Figures U.S. Patent Oct. 14, 1975 Sheet 1 of43,911,718

US. Patent Oct. 14, 1975 Sheet 2 of4 3,911,718

FIGZ B FIG?) WJ/W US. Patent Oct. 14, 1975 Sheet 4 Of4 3,911,718

HYDRAULIC EJECI'ION DEVICE BACKGROUND OF THE INVENTION The hydraulicejector device of this invention is intended for use in bolt makers,cold headers, cold nut formers, I-Ii-pro headers, progressive coldformers, hydraulic presses, punch presses, and injection molding pressesand similar types of machinery. The present invention provides a meansfor up-dating older equipment so that it will be more competitive withnewer machinery. It is a small, self-contained unit which can be readilyattached or detached from a piece of machinery. Also, it has only a fewparts so that it is simple to make and to maintain. A cooling factorincreases tool life.

An object of this invention is to provide a unitary, self-containedhydraulic ejector for use in part-forming machinery such as headers andpresses.

Another object of the invention is to provide such an ejector devicecomprising a few parts such as a casing with a through opening in whichare assembled a back plug, a piston reciprocable in a pressure chamberwith a forward extension, or with an intermediate or ejector pin, thedistal end of which forms a wall of a formedpart die at the front end ofthe ejector device.

Other objects and advantages of this invention will be apparent from theaccompanying drawings and description and the essential features will beset forth in the appended claims.

In the drawings,

FIG. 1 is a central sectional view through the first embodiment of thehydraulic ejector device of this invention with the ejecting pin in itsretracted position;

FIG. 2 is a view similar to FIG. 1 with the ejecting pin in itsprojected position;

FIG. 3 is a fragmental sectional view taken along the line 3-3 of FIG.2;

FIG. 4 is a schematic diagram showing the proposed hydraulic system foroperating the ejecting device of the first embodiment;

FIG. 5 is a central sectional view through a second embodiment with theparts retracted; while FIG. 6 is a view similar to FIG. 5 with the partsin ejecting position.

Referring now to FIGS. 1 and 2, a special holder or bolster is shown at10 which is specially designed to receive the hydraulic ejector deviceof this invention. It has a planar rear face 11 and a forwardlyprojecting sleeve 12 and a passageway shown at 13 permitting theintroduction of operating pressure fluid to the hydraulic ejectordevice. A central through opening 14 is provided to receive thehydraulic ejector device of this invention.

The unitary, self-contained hydraulic ejector unit 15 is generallycylindrical and adapted to slide into the opening 14 by entrance fromeither end. The ejector assembly is independently adjustable about itslongitudinal axis with reference to the holder. There is a cen- I tralthrough opening 16 through the casing 15, in which there are assembledthe following parts. Beginning at the rear end, at the right in FIG. 1,a threaded opening 17 receives a back plug 18 which is sealed againstthe bore 16 by an O-ring seal 19. Next is found a piston 20 whichpreferably has a rearward extension 20a and a forward extension 20b. Anannular pressure seal 21 fits tightly between an annular groove 22 andthe bore 16.

The forward piston extension 20b slides snugly in a reduced portion 16aof the central opening 16. As seen in FIG. 1, this abuts against thehead 23a of an intermediate or ejector pin 23, the head 23a being a snugsliding fit in the bore 16a. At the front end of the central opening ofthe casing there is inserted, as by a press fit, or otherwise, aformed-part die 24. This die conforms to the shape intended to beproduced and is here shown suitable for forming a head on a bolt or thelike. It will be noted in FIG. 1 that the wall 24a of the die is formedby the distal end of the ejector pin 23, which forms a piston rodejector extension.

The portion of the bore 16 in which the piston 20 travels forms acylindrical pressure chamber into which pressure fluid may be introducedto move the parts from the position of FIG. 1 to the position of FIG. 2.To this end, a plurality of openings 25 are provided extending throughthe walls of the casing 15 to receive pressure fluid introduced at 13.Referring to FIG. 3, it is desirable to have a plurality of openings 25spaced around the casing 15 so as to provide quick access of thepressure fluid over the entire piston 20. Preferably, a pressuredistributing chamber 26 is provided by an annular area cut into thespecial holder 10 radially outside of the casing 15 and opposite theopenings 25. An

annular area is cut into the outside diameter of the ejector case. Thisis required so as not to damage the ejector holder pressure seals.

Referring to FIG. 2, attention is called to the pressure chamber 16 andthe substantially equal pressureexposed areas 18a on the back plug 18and the combined areas 20 and 20a on the piston. Because of thisarrangement, when pressure fluid is introduced through 13 and 25, itexerts equal pressures both forward and rearward so that the ejector pin23 may eject the formed part with practically no tendency to cause anymovement endwise of the casing 15.

It will be noted that there are annular resilient pressure seals 27seated in suitable annular recesses in the holder 10. 7

It will be understood that in the use of this invention, the holder 10is positioned inthe platen or header slide so that the rear end of thecasing 15 is against one of the adjustable wedges 28 of one of the pressplatens while the work to be formed is manipulated by any standardtransfer device to position the part between the die 24 and the otherplaten (not shown) opposite the platen holding wedge 28.

Suitable mechanism is provided to introduce pressure fluid at 13 throughline A and to return the same to a main reservoir R through line B. Onesuch system is shown in FIG. 4. Electric motor M, through flexiblecoupling FC, drives a fixed displacement pump PF. This pump drawshydraulic oil from the reservoir tank R through a strainer ST and pumpsthe same into the accumulator ACC to the desired pressure setting whichmerely as a safety device to insure against malfunction of the pressureswitch or unloading valve and thus eliminating the possibility ofuncontrolled pressure build-up which would cause serious system damage.The twoway solenoid valve V is illustrated with a solenoid SB energized.In this position, the valve spool has been shifted to the returnposition. This is the period of the cycle in which the accumulator ischarged with the maximum system pressure. A pressure gauge PG is installed between the valve V and the accumulator to record the stand-bypressure of the system. The cam and micro-switch which is used tocontrol the valve V is not shown in this diagram.

During the forming operation of the machine cycle, the solenoid valve SBis energized as illustrated in FIG. 4. The cam for operating thesolenoid SB and SA is mounted on the end of the reciprocating crankshaft of the header or press and is adjusted to strike the solenoidvalve SB preferably at the forward dead center position of such crankshaft. This timing point is determined by the customer to meet hisparticular partsforming requirements. The timing may be set before deadcenter unlike mechanical units. When solenoid SA is so energized, thesolenoid SB is de-energized allowing the spool within the valve V to beshifted to the pressure position. At this time, the stored pressurefluid within the accumulator is allowed to disperse through the checkvalve C2 into the ejector E, thereby completing the ejection cycle. Asillustrated in FIG. 4, when the piston 20 in the ejector E is depressedmechanically inward, the hydraulic oil is forced through line B onthrough the check valve C3, after which it continues back through thetwo-way solenoid valve V and through a heat exchanger HE to cool it andthen on through a filter F back to the reservoir R. In fact thehydraulic oil is always directed through the cooler except during theejecting cycle. The ejector pin 23 remains in the position of FIG. 2until the next part to be formed is moved to the right in FIG. 2 by itsconnected platen which then pushes the parts 23 and 20 back to theposition of FIG. 1, being stopped by the back plug 18.

During the ejecting cycle, all pressures are contained within theejector casing 15, thereby eliminating practically all stress induced onthe bolster or on workstuds. Practically all mechanical type ejectorspresently known to me induce added strain and consequently wear onvarious machine members and parts. The ejector of this invention may beloaded and pressure applied with literally no physical means ofretaining the ejector casing within the holder 10. However, means forsecuring the ejector casing is provided. The part can be ejected and theejector device will remain practically stationary.

By designing into this system two check valves C2 and C3 with theiropposite free flow directions, the following has been accomplished.

a. The elimination of entrapping air between the valve V and the ejectorE. Entrappment of air at this point would cause a cushion effect on theejector piston, thereby lowering the effectiveness of the ejectorbecause of reduced oil pressure.

b. By expelling the total volume of oil in the ejector case back to thereservoir, a cooling effect of the ejector case is accomplished. Thismeans that cooler hydraulic oil is circulated through the casing at eachoperation of the cycle, thus cooling the part-forming insert 24. It isnot uncommon for dies in cold forming machinery to attain temperaturesin the area of 300 to 400 Fahrenheit. With this invention, the hydraulicfluid in the ejector unit is constantly being recirculated back to thereservoir tank R through the oil cooler or heat exchanger HE. Therecirculation of this fluid through the ejector unit will tend to carryaway some of the heat, thereby reducing the temperature of the formingdie which increases die life. This is an impor tant feature of thisinvention.

Another important feature is that the position of the parts in FIG. 1utilizing the sturdy construction of piston 20 and pin 23 stronglyresists the forming pressure exerted between the platens on the partresting in the die 24.

It should be understood that one or more ejector units may be connectedto lines A and B so as to eject a plurality of parts simultaneously orindividually.

A second embodiment of this invention is shown in FIGS. 5 and 6 of thedrawings. This shows a machine designed to make a socket head cap screw,or other similar object which needs a die male part as shown at 31 toform a female end on the work piece placed in the opening at 24. Herethe special holder 10 is like that previously described insofar as thepassage 13' is like the passage 13 mentioned in FIGS. 1 and 2. Anotheropening for the admission of hydraulic pressure fluid is indicated at32, as will presently appear.

Here the casing 33 has a central through opening into which is threadeda back plug 34 resting against the wedge 28' carried by one of theheader or press platens, then a movable piston 35 reciprocatable in thecylinder combustion chamber 36 and having an elongated extension 35aextending forwardly in an annular manner to a level at 35b (when theparts are retracted) where it becomes part of the die holding the pieceto be formed in the opening 24'. This die is indicated at 3'7 as being apress fit, or the like, at the left-hand end of FIGS. 5 and 6. The maledie part 31 is firmly fixed and supported by the male die extensionsupport pin 38 which is supported by a threaded pin 39 in the back plug34.

In this embodiment, the passages for introduction of hydraulic fluidthrough 13 to the compression chamber 36 includes a plurality ofpassages 25 supplied from an annular oil pocket 26 as described inconnection with FIGS. 1 and 2. However, the additional hydraulic fluidintroduction opening 32 is provided leading through an annular hydraulicfluid pocket 40 to a plurality of passageways 41 leading into thecompres sion chamber 36 to apply pressure on the down stream face of thepiston 35 when necessary.

Annular pressure seals are provided at all of the points indicated inthe drawings.

The operation of the second embodiment is like that described in thefirst embodiment in connection with FIG. 4. With the parts assembled asshown in FIG. 5, a piece to be formed is positioned in the opening 24 inthe die 37 by means carried by one of the platens of the header orpress. The platens at opposite sides of FIGS. 5 and 6 then are caused toapproach each other in the usual manner in headers or presses andforming pressure is applied on the piece to be formed which is firmlysupported by the casing 33, the die 37, the piston 35 and its extension35a, the same being backed up against the back plug 34 held by the wedge28', and by the male die 31, its supporting pin 38 and again thepressure being conducted through the back plug 34. When the part isformed, hydraulic pressure fluid is introduced through 13 and 25 to theright-hand end of compression chamber 36 causing the piston 35 and itsextension 35a to move forwardly to the position of FIG. 6, thusstripping and ejecting the formed socket head cap screw, or the like,moving it out of the indented chamber 24. Thereafter, hydraulic fluid isintroduced through the opening 32 and passageways 41 by means not shownto the left-hand end of the compression chamber 36, as viewed in FIGS. 5and 6, against the down stream face of the piston 35, thus moving itback to the starting position of FIG. 5.

The apparatus shown in FIGS. 1, 2, 5 and 6 can be adjusted to take careof changes in the die 24 or 37 as these dies become worn and arereground. The adjustment is limited by the distance between the points Aand B indicated on FIGS. 1 and 5.

It will be seen that this invention provides: (a) A doublc acting devicewhich acts as a stripper and ejector; (b) provides dissipation oftooling temperature (at dies 24 and 37) through recirculation ofhydraulic fluid through the heat exchanger HE and the reservoir R; (0)variable infinetely in precise timing, by adjustment of the cam foroperating the solenoid SB and SA, which cannot be accomplished withpresent mechanical devices; and (d) longitudinal adjustment of theejector within the ejector holder as noted in the dimensions A and B.

What is claimed is:

1. A unitary, self-contained hydraulic ejector for use in part-formingmachinery such as headers and presses; comprising a generallycylindrical ejector causing adapted to be held snugly in, andlongitudinally adjustable in, a complementary opening in a specialholder or bolster in a header or the like; there being a central throughopening in said casing; hydraulically operable piston-motor means insaid central through opening including a piston reciprocatable in apressure chamber and a piston rod ejector extension responsive tooperation of said motor means to eject a formed part, a back plugclosing the rear end of said through opening, there being a part-formingdie having an opening including pressure-receiving walls in the frontend of said casing in line with said ejector extension, there being anhydraulic pressure fluid passage through said casing communicating withsaid motor means pressure chamber in position to urge said piston-motormeans forward in an ejection direction, said parts in said casingthrough opening including a direct pressure-transmitting train innon-ejecting position from said pressure receiving walls to said backplug, said back plug being positioned to receive pressure directly froma press platen, and said cylindrical pressure chamber havingsubstantially equal pressure-exposed areas in opposite directions, oneon said back plug and one on said piston, practically eliminatingendwise stress, whereby said casing may be fixed in operating positionin a header or press and pressure applied in a known manner between twoplatens to form a part introduced into said part-forming opening, afterwhich hydraulic pressure fluid may be admitted to said piston-motormeans to eject the formed part.

2. An ejector as defined in claim 1, including an hydraulic fluidstorage reservoir, circulation means providing fluid flow from saidreservoir to said casing and means for return flow of said fluid fromsaid casing through a heat exchanger to said reservoir, whereby heat isconducted from said part-forming die through said casing and throughsaid parts in said central through opening to said hydraulic fluidbefore it returns to said reservoir.

3. An ejector as defined in claim 1, wherein said ejector extension isan intermediate pin in line with and in engagement with said piston ofsaid piston-motor means when said parts are in ready-to-eject position.

4. An ejector as defined in claim 1, wherein said ejector extension isan extension of said piston; there being a central through opening insaid piston and extension; a male die holding pin passes through saidlast named opening and is secured to said back plug; and means isprovided for supply of hydraulic pressure fluid through said casingselectively to opposite faces of said piston.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pat n 3.911.718Dated October I4 1975 Inventor(s) Robert E, Requarth It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Claim 1, line 3, "causing" should read casing".

Signal and Scalcd this I thirtieth Day of December 1975 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Ave-sting Officer Commissioner a] Forumand Trademarks

1. A unitary, self-contained hydraulic ejector for use in partformingmachinery such as headers and presses; comprising a generallycylindrical ejector causing adapted to be held snugly in, andlongitudinally adjustable in, a complementary opening in a specialholder or bolster in a header or the like; there being a central throughopening in said casing; hydraulically operable piston-motor means insaid central through opening including a piston reciprocatable in apressure chamber and a piston rod ejector extension responsive tooperation of said motor means to eject a formed part, a back plugclosing the rear end of said through opening, there being a part-formingdie having an opening including pressure-receiving walls in the frontend of said casing in line with said ejector extension, there being anhydraulic pressure fluid passage through said casing communicating withsaid motor means pressure chamber in position to urge said piston-motormeans forward in an ejection direction, said parts in said casingthrough opening including a direct pressure-transmitting train innon-ejecting position from said pressure receiving walls to said backplug, said back plug being positioned to receive pressure directly froma press platen, and said cylindrical pressure chamber havingsubstantially equal pressure-exposed areas in opposite directions, oneon said back plug and one on said piston, practically eliminatingendwise stress, whereby said casing may be fixed in operating positionin a header or press and pressure applied in a known manner between twoplatens to form a part introduced into said part-forming opening, afterwhich hydraulic pressure fluid may be admitted to said piston-motormeans to eject the formed part.
 2. An ejector as defined in claim 1,including an hydraulic fluid storage reservoir, circulation meansproviding fluid flow from said reservoir to said casing and means forreturn flow of said fluid from said casing through a heat exchanger tosaid reservoir, whereby heat is conducted from said part-Forming diethrough said casing and through said parts in said central throughopening to said hydraulic fluid before it returns to said reservoir. 3.An ejector as defined in claim 1, wherein said ejector extension is anintermediate pin in line with and in engagement with said piston of saidpiston-motor means when said parts are in ready-to-eject position.
 4. Anejector as defined in claim 1, wherein said ejector extension is anextension of said piston; there being a central through opening in saidpiston and extension; a male die holding pin passes through said lastnamed opening and is secured to said back plug; and means is providedfor supply of hydraulic pressure fluid through said casing selectivelyto opposite faces of said piston.